morton



Dec. 3, 1929. A. A. HORTON CONTROLLING MEANS FOR CALCULATING mcnmns 4 Sheets-Sheet 1 Filed Jan. 10, 1927 BY M Mia ATTORNEYJ Dec. 3, 1929. A. A. HORTON 1,738,144

CONTROLLING MEANS FOR CALCULATING MACHINES Filed 1927 4 Sheets-Sheet 2 A TTORNE Y Dec. 3, 1929. A. A. HORTON 1,738,144

CONTROLLING MEANS FOR CALCULATING MACHINES Filed Jan. 10, 1927 4 Sheets-Sheet 5 INVENTOR QCZw/ QM A TTORNE Y Dec. 3, 1929. A. A. HORTON CONTROLLING MEANS FOR CALCULATING MACHINES Filed Jan, 10, 1927 4 Sheets-Sheet 4 B Y W W Patented Dec. 3, 1929 UNITED STATES PATENT OFFICE ALLEN A. HORTON, OF PLYMOUTH. MICHIGAN, ASSIGNOR T BUR-ROUGHS ADDING MACHINE COMPANY, OF 'DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN CONTROLLING MEANS FOR CALCULATING MACHINES Application filed January 10, 1927.

This invention relates to controlling means for calculating machines. It relates particnlarly to an improvement for changing a calculating machine from one that will perform one function such as addition to one that will perform another function such as subtraction and vice versa.

Calculating machines are often conditioned for subtraction by moving a lever or key from one position to another. Generally, the

subtraction lever or key is automatically re turned to addition condition as the machine completes a subtraction operation so that it is necessary to move the lever or key to sub- 5 traction position each time a subtraction operation is desired. The present invention comprehends a construction in which, under normal conditions, the control lever is antomatically moved back to addition position at the end of each subtraction operation,

and, in addition, provision is made whereby special manipulation of the control lever when moved to subtraction position will cause it to remain in subtraction position until the control lever is manually released so that a number of subtraction operations may be performed without manipulating the control lever each time.

The general object of the invention is to provide an improved controlling means for calculating machines.

A more specific object is to provide an improved subtraction controlling mechanism which will normally be returned to addition position at the end of each subtraction oper- Serial No. 160.022.

control lever is moved to subtraction position and before the machine is operated.

Fig. 3 is a view similar to Fig. 2 showing the position of the parts at the end of a forward stroke of the machine with the control lever in subtraction position.

Fig. 4 is another view similar to Fig. 2 showing the position of the parts during the return stroke when the machine is operated to perform subtraction.

Fig. 5 is a view similar to Fig. 2 showing the position of the parts when the control mechanism has been set to cause the machine to remain in subtraction condition.

Fig. (i is a perspective view showing the principal parts of the improved controlling mechanism.

Fig. 7 is a section of the controlling mechanism on the line T7 of Fig. 2.

Fig. 8 is a separated perspective of the control lever and one of the yokes operated by it.

The controlling mechanism is shown in connection with the portable calculating machine now being marketed by the Burroughs Adding Machine Company, and While it is particularly applicable to this machine, it will be understood that it may also be used with other machines. The mechanism of the calculating machine itself will be described only generally as an understanding of its details is not necessary for an understanding of the present invention.

This machine has a main operating shaft 71 which is given a forward and a return stroke of movement by a handle or a motor, the direction of movement as viewed in Fig. 1 being first counter-clockwise and then clockwise. The shaft carries a driving plate having a stud 395 which, when the machine is conditioned for addition, passes the pawl 393 on the forward stroke of the machine. At the beginning of the return stroke this stud engages a shoulder on the pawl and moves the pawl rearwardly. pivoted to a pitman 387 which is thus moved rearwardly and it rocks a counter into engagement with actuator racks so that the amount set up in the machine is transferred The paw'i is i lUO to the counter during the return stroke. At the end of the return stroke a stud 200 also carried by the driving plate attached to the shaft 71 strikes the hooked end of a lower branch of the pitman 387 and moves the pitman forward to rock the counter out of engagement with the racks.

The machine is conditioned for subtraction by varying the action of the studs 395 and 200 on the pitman 387 and this is controlled by the subtraction control lever 10 which moves the link 363 rearwardly when the lever is moved from the addition position of Fig. 1 to the subtraction position of Fig. 2. Rearward movement of the link 363 rocks the bell crank yoke 362 counter-clockwise against the tension of a spring 364 which normally tends to rock the yoke in a clockwise direction and to maintain the subtraction control lever in addition position. Counter-clockwise movement of the yoke 362 rocks the lever 367 downwardly which, through the connections 406, moves the pawl 404 on the lower branch of the pit-man 387 into the path of the stud 200. Accordingly, at'the beginning of the forward stroke of the machine, the stud 200 strikes the end of pawl 404 and moves the pitman 387 rearwardly to rock the counter into engagement with the actuator racks at the beginning of the forward stroke instead of at the beginning of the return stroke as in the case of addition. The downward movement of the lever 367 also causes the downward or counter-clockwise movement of a lever 399 pivoted to pitman 387 so that the hooked end 400 of said lever moves into the path of the stud 395 and, at the same time, a central projection on the lever 399 swings the pawl 393 out of the path of the stud 395. With the parts in this condition, the stud 395 strikes the hooked end 400 of the lever 399 at the end of the forward stroke of the machine and pulls the pitman 387 forwardly to rock the counter out of engagement with the actuator racks at the end of the forward stroke. No movement of the pitman 387 takes place during the return stroke of the machine because the pawl 393 is out of the path of the stud 395 and, since the pitman is already in its forward position, the stud 200 does not act on the hooked end of the lower branch of the pitman at the end of the return stroke.

The rocking movement of the yoke 362 also sets a conditioning mechanism 439,436 434 so that operation of the machine condi tions the transfer mechanism to carry or borrow, depending on whether the machine is in condition for addition or subtraction. An understanding of the details of this control are not necessary for an understanding of the present invention.

When the machine is conditioned for addition, the control lever 10 is in its forward position where it is maintained by the tension of the spring 364.

When the machine is to be conditioned for subtraction, the control lever 10 is moved rearward to the position of Fig. 2 where it is locked by a latch plate 11 pivoted at 12 and having a shoulder 13 engaging over a square stud 14 on the link 363. The latch 11 is urged to latching position by a spring 15 and the latch acts to hold the subtraction control mechanism in subtraction condition against the tension of the spring 364.

The latch 11 may be released by depressing the error key E to the dot and dash position illustrated in Fig. 3. The stem of this key engages a beveled edge 16 on a sliding latch plate 223 which has a lateral lug 228 that engages the nose 17 on an upwardly extension portion of the latch plate 11. When the error key is depressed, the plate 223 moves forward to the dot and dash position of Fig. 3 which rocks the latch 11 to thefull line position thereby releasing the link 363 to permit the spring 364 to move the control mechanism toward its addition position.

The control mechanism does not immediately move to addition condition because it is otherwise under control of the machine. The initial release from the latching means takes place as above described but full release is not permitted until the machine has completed its subtraction operation and is near the end of the return stroke. The operation of the parts will be most easily understood by referring to Fig. 6.

The latch plate 11 is one arm of a yoke 18 which has a rearwardly projecting arm 19 to which is pivoted a pawl 20 having a tail 21 normally in the path of the stud 395 as shown in Fig. 1, so that, at the end of the forward stroke of the machine, the stud 395 engages the tail 21 and moves the pawl 20 to the position illustrated in Fig. 3. The forward end of the pawl 20 has a slot 22 for the reception of a lateral lug 23 on one arm 24 of a yoke 25 having another cam-shaped arm 26 which engages the lower end of the control lever 10 as illustrated in Fig. 8. The arm 24 of yoke 25 is urged in a clockwise direction by the spring 27 which also serves to urge the pawl 20 in a clockwise direction. When the parts are in normal position the lateral lug 23 is in the slot 22 and, when the stud 395 contacts the tail 21, of the pawl 20 the arm 19 of the yoke 18 is rocked counterclockwise which moves the latch 11 upwardly to the position of Fig. 3 thereby unlatching the link 363 to permit it to be moved forward by the spring 364. The control mechanism cannot return immediately to its addition condition as such movement would be undesirable at the end of the forward stroke. The complete return is deferred until at the end of the return stroke by mechanism as follows:

The control lever 10 has two slots 30 and 31 engaging over pins 32 and 33 respectively carried by one arm 34 of a bell crank lever,

to which arm the link 363 is also connected, said bell crank lever having a forwardly extending arm 35 that has an interlocking engagement with a control rod 191. This control rod is moved rearwardly from the position of Fig. 2 to that of Fig. 3 during each operation of the machine. An understanding of the mechanism for doing this is not necessary here, it being sufficient to know that the rod 191 moves rearwardly during the forward stroke of the machine and is returned forwardly during the return Stroke. At the end of the forward stroke of the machine during a subtraction operation, the control 191 underlies the arm 35 of the bell cr ank lever, thereby preventing counter-clockwise movement of said lever. There is a slight clearance between the control rod and lever as illustrated in Fig. 2 by dotted lines so that, at'the end of the forward stroke, when the stud 395 strikes the tail 21 of the pawl 20, the latch 11 and associated parts may be rocked slightly counter-clockwise, the distance of movement being represented by the clearance between the arm 35 and the control rod 191. This is sufficient to move the shoulder 13 of the latch 11 above the square stud 14 on the link 363 so that the link is unlatched, but it can move only a limited distance forwardly under the tension of spring 364 because of the contact of the arm 35 of the bell crank lever with the control rod 191.

The link 363 moves far enough forward so that when the latch 11 drops back it will drop on top of the stud 14 as shown in Fig. 4 and thereby prevent relatching or locking of the link 363. At the end of the return stroke of the machine, the control rod 191 clears the end of the arm 35 whereupon the spring 364 may move the link 363 forwardly and swing the control mechanism in a counter-clockwise direction to return it to addition condition. It will thus be seen that the control mechanism is unlatched at the end of the forward stroke and permitted to have a limited movement, but it is prevented from returning to addition condition until at the end of the return stroke when it is released.

If it is desired to have the control mechanism remain in subtraction condition in order to perform a number of subtraction operations without having to move the control lever to subtraction position each time, the control lever 10 is pressed downwardly after it has been moved to subtraction position. This moves the lever on its pin and slot connection with the arm 34 and the downward movement of the lever causes its lower end to rock the arm 26 of the yoke 25 to thereby rock the arm 24 to move the lateral lug 23 out of the slot 22 in the pawl 20. The connection between the pawl 20 and the arm 24 is thus broken and when the stud 395 strikes the tail 21 of the pawl 20 at the end of the forward stroke, the pawl is merely rocked slightlv about its pivot on the arm 19 against the tension of spring 27 but no movement of the arm 19 takes place to unlatch the latch plate 11. Accordingly, the control mechanism remains locked in subtraction condition without being affected by the operation of the machine. The control lever 10 is maintained in its lower osition by a spring deten 36 which engages in the notches 37 and 38 in the edge of the lever. This detent maintains the lever in its lower position illustrated in Fig. 5 with sufficient rigidity to prevent it from being moved upwardly by the tension placed on the spring 27. It is possible to depress the lever 10 to its lower position while the lever is in addition position in which event the parts will act as above described when the lever is moved to subtraction position, but the preferable mode of operation is to first move the lever to subtraction position and then depress it if successive subtractions are desired.

\Vhen it is desired to again condition the machine for addition the lever 10 is pulled upwardly and retained in that position by the spring detent 36 engaging in the lower notch 38. The rocker arm 26 follows lever 10 under the tension of spring 27 and the lug 23 is swung into slot 22 in pawl 20 which places the parts in their normal condition. After the lever 10 is raised. it may be restored to adding position by depressing the error key which unlatches the link 363 and the latter together with the lever 10 is moved to addition position by action of the spring 364.

From the disclosure thus made it will be clear that a control mechanism has been provided by means of which a calculating machine may be conditioned for addition or subtraction with the mechanism arranged so that under normal condition the machine automatically returns the controlling mechanism to addition condition after the performance of a single subtraction operation, but by simply pressin down on the control lever when it is in su traction condition, the parts may be positioned so that the machine will remain in subtraction condition for a series of operations without being automatically returned by operation of the machine. This provides a very simple method of control and eliminates additional keys or controlling levers.

It is to be understood that the structure shown is for purposes of illustration and that variations may be made in it without departing from the spirit and scope of the invention as defined by the appended claims.

Although the control lever has been explained in connection with the conditioning of a machine for addition and subtraction it will be clear that the action of the control mechanism is not dependent upon the exact functions of the machine that are controlled -by the control mechanism. The control lever might be employed to condition the machine for other operations as well as for addition and subtraction.

I claim:

1. The combination in a calculating machine of a control lever movable from addition to subtraction position and "ice "ersa, means for urging said lever toward addition position, latching means for holding said lever in subtraction position when moved to said position, means actuated by operation of the machine to release said lever at the end of the forward stroke of the machine to permit it to move toward addition position, and means for limiting the movement of said lever toward addition position until near the end of the return stroke of the machine and at that time fully releasing it for return to addition position.

2. The combination in a calculating machine of a controlling means normally occupying one position Where it conditions the machine to perform one function but movable to another position to condition the machine to perform another function, means for automatically returning the controlling means to its first position after the machine has performed a function with the controlling means in its second position, and connections controlled by special manipulation of said controlling means acting to prevent the controlling means from being automatically returned to its first position.

3. The combination in a calculating machine of a controlling means normally urged to a position where it conditions the machine to perform one function but movable to another position where it conditions the machine to perform another function, means for latching the controlling means in its second position when moved thereto, means acting to automatically release said latching means at each operation of the machine, and connections operated by special manipulation of said controlling means for preventing release of the latching means by operation of the machine.

4. The combination in a calculating machine of a control lever movable from addition to subtraction posit-ion and vice versa, means for urging said lever to addition position, latching meansfor holding the lever in subtraction position when moved to said position, means actuated by operation of the machine for releasing the lever to permit it to move to addition position after a subtraction operation has been performed, said lever being movable substantially at right angles to its direction of movement from addition to subtraction position. and connections operated by said lever when moved in said right angular direction to prevent the lever from being unlatched by operation of the machine.

5. The combination in a calculating machine of a pivoted control lever movable from addition to subtraction position and vice versa, means for urging said lever towards its addition position, latching means for bolding the lever in subtraction position when moved to said position, means actuated by operation of the machine for releasing the latching means, said lever being movable longitudinally, and connections operated by longitudinal movement of said lever for preventing operation of the machine from unlatching the latching means.

6. The combination in a calculating machine of a controlling means including a pivoted lever movable from one position to another to condition the machine to perform different functions, means for normally returning it to its first position at each operation of the machine. and connections operated by depressions of said lever for preventing it being returned to its first position by operation of the machine.

7. The combination in a calculating machine of a controlling means including a control lever movable from one position to the other to condition the machine to perform different functions, said lever being normally returned to its original position at each operation of the machine, and means operated by movement of said lever at right angles to its first path of movement for preventing operation of the machine from returning the lever to its normal position.

8. The combination in a calculating machine of a controlling means for conditioning the machine for addition or subtraction, a lever swingable from one position to another for setting said mechanism, means for latching the lever in subtraction position when moved to said position, means for unlocking the latching means by operation of the machine, and connections operated by depression of the lever for preventing operation of the machine from unlatching the latching means.

9. The combination in a calculating machine of a controlling means including a control lever movable from addition to subtraction position, means for normally urging the lever towards addition position, a latch for holding the lever in subtraction position when it is moved to said position, means actuated by operation of the machine for releasing the latch at the end of the forward stroke of the machine, means for preventing the controlling means from moving to addition position when released at the end of the forward stroke, said latteruneans acting to release the controlling means at the end of the return stroke to permit the controlling means to move to addition condition.

10. The combination in an accounting machine of a controlling means including a control lever movable from addition to subtraction position, means for normally urging the control lever toward addition position, a-

latch for holding the lever in subtraction position when it is moved to said position, means operated by the machine during a stroke of operation for unlocking the latch, 5 and connections operated by depression of the control lever for breaking the connection between the latch releasing means and the latch.

11. The combination in a calculating mam chine of a controlling means including a pivoted control lever operating a link, means for urging the lever and link toward addition position, a latch acting on the link for holding it in subtraction position when 15 the lever is moved to said position, means operated by actuation of the machine for releasing the latch when the machine is operated to perform subtraction, and connections operated by depression of the control lever for 20 breaking the connection between the releasing means and the latch to prevent operation of the machine from releasing the controlling means.

In testimony whereof, I have subscribed 25 my name.

ALLEN A. HORTON. 

